I don't know if Keller WIlliams has a downtown NY office, but if you go to KW.com and search for the nearest brokerage, you can call that office and they can tell you if there are plans to open one. I am too far away and wouldn't know.
Keller WIlliams has business plans and trains you from the beginning to work for yourself, not your brokerage. I don't think there is any other model like it. Everything about them is designed to serve the agents. KW also has sample business plans, etc. Go to agentmountain.com - you can create a guest account and use alot of the resources free. You see, Keller WIlliams believes in sharing.... even if you're not with the brokerage. It is a whole different kind of culture compared to elsewhere. One disclaimer - KW is not for those that are not serious about their careers. They will give you all the resources you could ever want, tons of support, and everything you need. But, you must work to develop your own business. It is seriously hard work, and rather expensive. You'll know what I mean if you survive. Most don't. Beat the odds.
I've developed a list of agent in the NY area, and I'd be glad to put you in touch with people that might be able to help you. Feel free to call me... but today, I am taking the day off to play with my babies. Tomorrow, I'll be "back at it" and fully available if you want to talk.